1. Field of the Invention
The present invention relates to a flash device, preferably for transferring dye particles by means of high-energy light flash and a micro-optic focusing array, from a radiation-absorbing dye carrier onto a receiver element, e.g. a glass plate or the like.
2. Background
Liquid crystal display devices are known for digital display in electronic calculators, clocks, household appliances, audio equipment, etc. Liquid crystal display devices are being developed to replace cathode ray tube technology for display terminals because they occupy smaller volume than cathode ray tube devices, are lighter than cathode ray tube devices occupying the same screen area and, have lower power and voltage requirements than corresponding cathode ray tube devices.
A liquid crystal display requires a color filter array (CFA) as one of its components. One commercially available type of a color filter array that has been used in liquid crystal display devices is a transparent support having a polymer receiver layer (such as a gelatin layer) thereon which contains red, blue and green dyes arranged in a mosaic pattern obtained by a photolithographic process. The photolithographic process involves a large number of steps. These steps include cleaning the support, coating it, exposing it to light and then developing it, drying it, etching it and stripping it for each of the three dye colors. Details of this process are disclosed in U.S. Pat. No. 5,229,232 (background section) and U.S. Pat. No. 4,081,277. Because of the large number of steps involved in the photolithographic process, such color filter arrays are relatively expensive to manufacture. In addition, misalignment or improper deposition of color materials may occur during this process, reducing the quality of the color filter array.
One promising method to reduce the cost of color filter array manufacture is a thermal dye transfer method described in U.S. Pat. No. 4,923,860, U.S. Pat. No. 5,229,232 and U.S. Pat. No. 5,309,329. In the method described therein, the color filter array is formed in a relatively few steps by thermally transferring a dye from a radiation absorbing dye donor to a receiver element.
More specifically, the embodiment described in U.S. Pat. No. 5,309,329 uses a non-photolithographic contact printing method. The method disclosed in this patent utilizes a powerful plasma discharge tube to produce a high-energy flash. The light resulted from this flash is then transferred through a mask to an adjacent radiation absorbing dye carrier (also refereed to as dye donor), from which the dye sublimates onto an adjacent receiver element.
It is the principal object of the present invention to improve the above-describe thermal dye transfer method by providing a more energy efficient flash device.
Another object of the present invention is to create an improved flash device that eliminates the problem of mask abrasion, which occurs in contact printing methods that use masks.